Clonal Diversity and Sex Ratio of a Malaria Parasite

疟疾寄生虫有一个复杂的生命周期，包括在脊椎动物宿主(包括人类和许多野生动物物种)的血细胞内进行无性繁殖(细胞分裂)，以及在食血昆虫内进行有性繁殖。寄生虫在血细胞中产生雄性和雌性性细胞(配子体)，这些细胞在昆虫体内交配。尽管疟疾寄生虫的生命周期早在一个世纪前就已为人所知，但有一个特征仍然是个谜：为什么配子体性别比在不同的疟原虫物种之间会有所不同，甚至在任何一个物种的感染之间也会有所不同。这项研究将首次研究自然疟疾系统的分子遗传学，以检验进化生物学的支柱--性别比理论。它将通过使用感染爬行动物宿主的疟原虫进行实验，研究寄生虫的遗传多样性如何影响雄配子体和雌配子体的比例(性别比)。这些实验将检验这样一种假设，即这些配子细胞的性别比例取决于遗传上相同的配子细胞之间发生配对的频率。这些实验还将检验这一假设，即寄生虫能够监测单个感染者体内亲属和非亲属的存在。疟疾每年导致数百万人死亡，是许多野生动物的一种重要疾病。寄生虫的遗传多样性被认为在它们的生物学包括传播和毒力方面起着重要作用，因此这项研究的结果可能为治疗这种疾病提供重要信息。此外，该项目还将培训至少10名本科生和研究生。

Malaria parasites (Plasmodium) have a complex life cycle that consists of asexual reproduction (cell division) within the blood cells of vertebrate hosts (including humans and many wildlife species), and sexual reproduction within a blood-feeding insect. The parasites produce male and female sex cells (gametocytes) in blood cells, and these mate within the insect. Although the life cycle of the malaria parasite has been known for a century, one feature remains a mystery: why gametocyte sex ratio varies among Plasmodium species and even among infections for any one species. This study will be the first to study the molecular genetics of a natural malaria system to test sex ratio theory, a mainstay of evolutionary biology. It will examine how the genetic diversity of the parasite influences the ratio of male and female gametocytes (sex ratio), with experiments using a Plasmodium that infects a reptile host. The experiments will test the hypothesis that the sex ratio of those gametocytes is determined by how often matings occur between gametocytes that are genetically identical. The experiments will also test the hypothesis that the parasites are able to monitor the presence of kin and non-kin within a single infected individual. Malaria kills millions of people every year and is an important disease of many wild animals. The genetic diversity of parasites is thought to play a major role in their biology, including transmission and virulence, so the results of this study may provide important information for treating this disease. In addition, this project will result in the training of at least 10 undergraduate and graduate students.